Omega-3 Fatty Acids

What Are Omega-3 Fatty Acids?

Omega-3 fatty acids are a family of polyunsaturated fatty acids characterized by a double bond at the third carbon from the methyl (omega) end of the fatty acid chain. The three most nutritionally significant omega-3s are:

• ALA (alpha-linolenic acid, C18:3n-3): a plant-derived essential fatty acid found in flaxseed, chia seeds, and walnuts
• EPA (eicosapentaenoic acid, C20:5n-3): a long-chain omega-3 found in fatty fish and algae; exerts anti-inflammatory effects
• DHA (docosahexaenoic acid, C22:6n-3): a long-chain omega-3 critical for brain and retinal structure; found in fatty fish and algae

ALA is classified as essential because the human body cannot synthesize it. EPA and DHA can be synthesized from ALA, but the conversion efficiency is very low (typically less than 10%), making direct dietary intake important.

Health Benefits

Omega-3 fatty acids, particularly EPA and DHA, have well-documented health benefits:

• Cardiovascular: reduce triglycerides, lower blood pressure, reduce platelet aggregation, and decrease risk of fatal cardiac arrhythmias
• Neurological: DHA is a major structural component of the brain and retina; adequate intake supports cognitive development and may reduce risk of dementia
• Anti-inflammatory: EPA is a precursor to anti-inflammatory eicosanoids; beneficial in inflammatory conditions such as rheumatoid arthritis
• Prenatal: DHA is critical for fetal brain and eye development

Recommended Intake and Food Sources

The AI for ALA is 1.6 g/day for men and 1.1 g/day for women. Most health organizations recommend consuming at least 250–500 mg/day of combined EPA + DHA. The American Heart Association advises eating fatty fish twice per week.

• Atlantic salmon (100 g cooked): ~2,150 mg EPA+DHA
• Mackerel (100 g cooked): ~3,200 mg EPA+DHA
• Chia seeds (28 g): ~5,000 mg ALA
• Walnuts (28 g): ~2,570 mg ALA